A fixing device for digitally written and re-erasable offset printing forms is known for example from DE 100 08 213 A1. This device carries out the fixing by homogeneously heating the printing form surface. There, following imaging from the stock of digital data, the printing form is fixed for improved durability, wherein the ink-carrying image parts are anchored to the printing form. For this purpose, the fixing operation is carried out by means of inductively heating the image on the rotating printing form. To that end, the printing form is made of a material suitable for induction heating, and in a particularly advantageous way the frequency of the alternating current for inductive coupling is in the medium frequency range from 100 kHz to 500 kHz.
During the injection of energy by induction, heating in the interior of the metallic printing form is brought about by means of a high-frequency alternating current. As a result of what is known as the skin effect, the heating can either be placed intensely at the surface by means of high frequencies or else further into the interior of the material by means of lower frequencies. The injection of energy is in this case restricted zonally, which is advantageous in particular with regard to the power consumption. As a result of the heating of the metallic printing form, the image information previously applied to the printing form surface (consisting of thermal material in the present case) is stabilized.